What I don’t know is if the expansion rate for the gases vented by the brake would develop a significant pressure on the shroud (filling it and then developing a positive/higher atmosphere) before the bullet exits and allows a pressure drop since the forward gas direction is no longer impeded by the bullet in the barrel. If XM193 cronos ~3k fps at muzzle, that means the bullet’s dwell time inside the ~2″ muzzle device is only ~0.000055 of a second (if my calc is correct) before it leaves the muzzle device into open/clear air. I’m asking could the gas be working like it was blowing off into clear air because the bullet gets away before backward pressure develops inside the shroud (not the barrel). Verses in this arrangement some/more of the gases leave the muzzle’s profile (east west into the shroud) BEFORE the bullet exits the device, in effect bleeding off some gases and applying gas pressure inside the shroud VERY shortly before the bullet leaves the muzzle device. I’m not sure if this is an answer but wonder if as a regular un-braked muzzle (plain old crowned barrel) has the majority of gas pressure released ONLY behind the bullet’s exit into clear air it develops most recoil while bullet is impeding forward gas flow and thus develops reward pressure (recoil). I hear what your saying BUT having shot this it does continue to mitigate muzzle rise (not sure about reward-recoil, I was not focussed on that). The gas being directed into the shroud by the muzzle brake has not left the gun, because it is still contained by the shroud, which is part of the gun. Only the direction of the gas as it leaves the gun matters. In order for the brake to work, the gas coming out of it must leave the gun entirely while being directed up and/or to the rear. Its velocity may be reduced by being allowed to expand somewhat before exiting, but every action creates an equal and opposite reaction – muzzle blast goes forward, the gun moves to the rear. The only thing that matters is where the gas finally exits the system. This is like trying to push a car by sitting in the back seat and pushing against the seat in front of you. The fact that the gas is first directed to the sides or rear by the brake doesn’t matter the gas coming out of the brake can’t possibly reduce recoil because it is pushing against a component of the gun (the shroud) instead of against the outside air. If the shroud over the muzzle brake is directing gas forward, then the shroud must be contributing to recoil.

My long-ass monkey arms are more suited to a 20 inch AR barrel, but I still have to go in and out of vehicles and doors, just like everyone else. This means my I often end up holding thumb-over-muzzle, which hasn’t really caught on yet as a shooting stance. I want a carbine length (or shorter) AR, but I hold thumb-over-bore. Tall shooters like me often have to get cramped up on an AR in a very uncomfortable posture. There’s another benefit that comes from Kineti-Tech’s combination, and that is the protection of your support hand. The muzzle brake functions well, and helps hold down recoil, and the addition of the sleeve doesn’t change that. We shot several magazines through this AR and could see no change in accuracy. If I were shooting with anyone else–fighting, competing, whatever–I’d want one. And it is much easier to stand beside the gun. That said, it would be much safer to shoot an AR with one of these sleeves and no ear protection. It is not so quiet that I’d take off my ear protection. So I put it back together and pulled the trigger again.

When you reach out on the forend, you run the risk of reaching too far, but less so with the sleeve installed.

Ar15 muzzle breaks